This invention relates to a boiler for steam flatirons, of a type which comprises a tight receptacle having a replenishment manifold.
A trend of ironing appliances comprising a separate flatiron from a boiler has been toward an increase of the boiler capacity so as to expand their autonomy of operation.
When the boiler capacity is increased, however, it is to be expected that, for a given available power, the times required for steam rising and the appliance to attain steady state operation are bound to increase proportionally.
This entails conflicting requirements. For instance, there are some who favor quick attainment of steady state by the flatiron and boiler, to the detriment of autonomy of operation, and others who place prolonged autonomy of operation before a short time of attainment of the thermal state required for proper ironing.
With prior boilers which are equipped with a filler inlet cut through the ceiling of the tight receptacle, such conflicting demands are reconciled by adopting a procedure of metered boiler replenishment whereby a small amount of water is introduced into the boiler when a fast heating rate of the water is aimed at, and a large amount of water whenever it is autonomy of ironing that gains priority.
However, at the end of the ironing operation, the residual water is not customarily taken out of the boiler, and on the next ironing occasion, the boiler has to be topped up.
Since it is no easy task to assess the exact amount of water left over in the boiler, the topping up process is of necessity a pretty inaccurate one, thereby it may happen that the amount of water introduced is either too small--which is apt to involve renewed topping up within a short time and attendant time allowance for the boiler to cool down--or too large--which enforces an extension of the time required to raise the pressure within the boiler to the operating range.
This constitutes a first drawback of prior boilers.
A further drawback, connected with manufacture aspects of the ironing appliance, is that a large number of components are to be mounted separately to the boiler; these components include safety valves, steam delivery lines, filler caps, etc.
In an effort to alleviate the manufacturing process, some of these components have been clustered; for instance, it is widespread practice to mount the boiler safety valve in a seat specially formed in the filler cap. This installation, however, provides no optimum solution to the problem of the operator's own safety.